The present invention relates to beam-lead chip structures and assemblies, and methods for forming such structures and assemblies. The beam-lead structure is probably the most widely used expedient for connecting an integrated circuit chip to a conductive land pattern on a dielectric supporting substrate which provides the pluggable integrated circuit assembly. The standard planar integrated circuit comprises a semiconductor chip substrate having a planar surface from which the active and passive devices extend into the substrate. The surface is passivated with a layer of electrically insulative material, e. g. a glass such as silicon dioxide, and the metallic interconnector pattern which interconnects the devices into the integrated circuit is disposed on this insulative layer, selectively connected to devices by contacts which extend through the layer. The interconnector pattern may be covered by a further layer of insulative material. In the conventional beam-lead structures, a plurality of beam-leads formed on the level of said interconnector pattern and connected to said pattern extend in a cantilevered fashion beyond the chip periphery. These beam-leads are conventionally connected to a plurality of corresponding land leads on the dielectric substrate.
A significant problem in beam-lead technology remains the development of fast, effective and efficient means for bringing the chip beam-leads into registration with the corresponding land leads in order that effective bonding may be accomplished. To date, it is believed that the most effective way of bringing the beam-leads into registration with the corresponding land leads remains manual positioning under a microscope. Unfortunately, with the rapidly decreasing size of integrated circuit chips and the corresponding high rate of densification of circuitry and connectors, the beam-leads and the spacing between them are shrinking to the point that manual positioning will no longer be possible.
Once the positioning has been completed, the bonding of the beam-leads to the corresponding land leads is accomplished by standard bonding apparatus such as the bonding apparatus described in U.S. Pat. Nos. 3,475,814 and 3,672,034.
In addition, in beam-lead integrated circuit chips as in all integrated circit chips, with the increasing device densities of large scale integration, there is an ever-increasing need to conserve the maximum semiconductor substrate "real estate" in device fabrication.
In addition, there is a need for a beam-lead integrated circuit chip structure wherein the beam-lead metallurgy does not encroach upon or interfere with the layout of the interconnector metallization.